Add production Dockerfile for self-hosted deployment

[forge-atlas]

Summary

• Multi-stage Dockerfile using oven/bun:1 — deps install, Next.js build with standalone output, and slim production runner
• App service added to docker-compose.yml with postgres healthcheck dependency and redis-rest
• .env.docker template with Docker networking defaults (postgres:5432, redis-rest:80) and placeholder secrets
• docker-entrypoint.sh runs prisma migrate deploy automatically on container startup
• Next.js standalone output enabled in next.config.ts for minimal production image

Usage

cp apps/web/.env.docker apps/web/.env
# Edit apps/web/.env with your GitHub OAuth credentials and secrets
docker compose up
# App available at http://localhost:3000

Test plan

• docker compose build completes without errors
• docker compose up starts all services (postgres, redis, redis-rest, app)
• Prisma migrations run automatically on first boot
• App accessible at http://localhost:3000
• GitHub OAuth login works with correct client ID/secret configured

🤖 Generated with Claude Code

[forge-atlas]

Closing in favor of openformation#1 (opened against the upstream repo per request)